Halloween is not recognized as a federal or national holiday in the United States. However, the federal government does acknowledge it as a recognized American holiday.
Halloween has deep roots and a rich history worldwide. It is thought to have originated from the ancient, pre-Christian Celtic festival Samhain, which was the most significant holiday of the Celtic year. During the first millennium A.D., Christian missionaries began to transform the celebration into the modern version of Halloween. The missionaries began identifying the deities previously celebrated by the Celts as evil demons, which contributed to the sinister, supernatural tone Halloween is associated with today. The day after Halloween, Nov. 1, was named All Saints Day, a holiday for praising all the saints of Christianity and bringing the Celts a new Christian celebration.